[PATCH 5.10 17/36] perf map: Fix error return code in maps__clone()

[Greg Kroah-Hartman]

From: Zhen Lei <thunder.leizhen@xxxxxxxxxx>

[ Upstream commit c6f87141254d16e281e4b4431af7316895207b8f ]

Although 'err' has been initialized to -ENOMEM, but it will be reassigned
by the "err = unwind__prepare_access(...)" statement in the for loop. So
that, the value of 'err' is unknown when map__clone() failed.

Fixes: 6c502584438bda63 ("perf unwind: Call unwind__prepare_access for forked thread")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: zhen lei <thunder.leizhen@xxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20210415092744.3793-1-thunder.leizhen@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/perf/util/map.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index e2537d5acab0..f4d44f75ba15 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -836,15 +836,18 @@ out:
 int maps__clone(struct thread *thread, struct maps *parent)
 {
 	struct maps *maps = thread->maps;
-	int err = -ENOMEM;
+	int err;
 	struct map *map;
 
 	down_read(&parent->lock);
 
 	maps__for_each_entry(parent, map) {
 		struct map *new = map__clone(map);
-		if (new == NULL)
+
+		if (new == NULL) {
+			err = -ENOMEM;
 			goto out_unlock;
+		}
 
 		err = unwind__prepare_access(maps, new, NULL);
 		if (err)
-- 
2.30.2